A physician typically accesses and visualizes tissue within a patient's gastrointestinal (GI) tract with an endoscope (such as a gastroscope or a colonoscope) having a long, flexible insertion tube. For the upper GI, a physician may insert a gastroscope into the sedated patient's mouth to examine and treat tissue in the esophagus, stomach, and proximal duodenum. For the lower GI, a physician may insert a colonoscope through the sedated patient's anus to examine the rectum and colon. Some endoscopes have a working channel in the insertion tube, typically about 2.5-3.5 millimeters in diameter, extending from a port in the handpiece to the distal portion of the insertion tube. A physician may insert medical devices into the working channel to help diagnose or treat tissue within the patient.
Guidewires have been used to aid the introduction of catheters (such as insertion tubes of endoscopes) and other instruments into many sites in the human body. Many medical applications and specific designs of guidewires have been for cardiovascular use. There are, however, specific challenges relating to the use of guidewires in the GI tract, as opposed to the vascular system. Thus, the bowel is more tortuous, softer and generally of larger diameter. Furthermore, in the case of the small intestine and the colon, these are longer than most arteries or veins.
Still, scientists and engineers continue to seek improved guidewire structures having a medical guidewire.